The R2R3-MYB Transcription Factor Gene Family in Maize

Abstract

MYB proteins comprise a large family of plant transcription factors, members of which perform a variety of functions in plant biological processes. To date, no genome-wide characterization of this gene family has been conducted in maize (Zea mays). In the present study, we performed a comprehensive computational analysis, to yield a complete overview of the R2R3-MYB gene family in maize, including the phylogeny, expression patterns, and also its structural and functional characteristics. The MYB gene structure in maize and Arabidopsis were highly conserved, indicating that they were originally compact in size. Subgroup-specific conserved motifs outside the MYB domain may reflect functional conservation. The genome distribution strongly supports the hypothesis that segmental and tandem duplication contribute to the expansion of maize MYB genes. We also performed an updated and comprehensive classification of the R2R3-MYB gene families in maize and other plant species. The result revealed that the functions were conserved between maize MYB genes and their putative orthologs, demonstrating the origin and evolutionary diversification of plant MYB genes. Species-specific groups/subgroups may evolve or be lost during evolution, resulting in functional divergence. Expression profile study indicated that maize R2R3-MYB genes exhibit a variety of expression patterns, suggesting diverse functions. Furthermore, computational prediction potential targets of maize microRNAs (miRNAs) revealed that miR159, miR319, and miR160 may be implicated in regulating maize R2R3-MYB genes, suggesting roles of these miRNAs in post-transcriptional regulation and transcription networks. Our comparative analysis of R2R3-MYB genes in maize confirm and extend the sequence and functional characteristics of this gene family, and will facilitate future functional analysis of the MYB gene family in maize.

MYB transcription factor genes as regulators for plant responses: an overview

“…The MYB gene family is represented by only five 3R-MYB genes, compared with up to 190 R2R3-MYB genes in Arabidopsis (Stracke et al 2001;Yanhui et al 2006). Recently, Du et al (2012a) performed a genome-wide survey of the R2R3-MYB gene family in maize and identified a putative full set of R2R3-MYBs in the maize genome, comprising a total of 157 typical R2R3-MYB encoding genes. The Populus genome contains five 3R-MYB genes and 192 R2R3-MYB genes (Wilkins et al 2009).…”

“…While C1 is active in aleurone, a very similar MYB protein, P1, is functional in controlling anthocyanin biosynthesis in the maize plant where it interacts with other members of the R-protein family to activate anthocyanin biosynthetic gene expression (Cone et al 1993). In maize, another MYB protein, ZmMYB1 activated the structural genes required for anthocyanin biosynthesis while ZmMYB38 inhibited C1-mediated activation of the same promoter (Du et al 2012a).…”

Overexpression of a novel SbMYB15 from Salicornia brachiata confers salinity and dehydration tolerance by reduced oxidative damage and improved photosynthesis in transgenic tobacco

“…MYB proteins are classified into four subfamilies, namely R1-MYB, R2R3-MYB, 3R-MYB, and 4R-MYB, depending on the number of adjacent repeats in the MYB domain (Dubos et al 2010). The R2R3 MYB family is highly represented in plants: with more than 157 in maize (Du et al 2012) and more than 100 in Arabidopsis (Chen et al 2006), and is considered to have evolved from an ancestral R1R2R3 type (Braun and Grotewold 1999).…”

Characterization of a New Pink-Fruited Tomato Mutant Results in the Identification of a Null Allele of the SlMYB12 Transcription Factor

“…1). More than 70 different flavonoids have been identified in tomato fruit, including glycosylated and other conjugated forms (Moço et al, 2006;Mintz-Oron et al, 2008;Iijima et al, 2008;Adato et al, 2009;Ballester et al, 2010 (Grotewold et al, 1994;Chopra et al, 1996;Kranz et al, 1998;Stracke et al, 2007;Adato et al, 2009;Czemmel et al, 2009;Ballester et al, 2010;Lin-Wang et al, 2010;Hichri et al, 2011;Du et al, 2012;Nakatsuka et al, 2012). Specific R2R3-MYB transcription factors (TFs) capable of regulating the expression of genes in the flavonoid branch are characterized by the presence of the SG7 motif (Kranz et al, 1998;Stracke et al, 2007;Czemmel et al, 2009), which is positioned downstream of the R2R3 DNA-binding domain.…”